Article



Sept. 17, 1935.

E. E. FRANZ ARTICLE Filed April 28, 1935 FIG.

MA R VF m. E

A TTOR/VEV Patented Sept. 17, 1935 UNITED STATES PATENT OFFICE C mpany.

rporated, New

em York, N. Y., a corporation of New York Application April 28, 1933, Serial No. 668.305

priate dielectric material of the designer trace of a spiral coil or other desired electrical member in a graphite ink or other conducting medium. The two printed traces extend to a common point at one of the principal edges of the sheet or to a common point at the edge of a preformed perforation in the sheet. The traces are then coated with copper or other conductor substance and the gap between the two traces is bridged by the coating process although there is no contact between the traces. The resulting dielectric sheets bearing the continuous conducting members thus formed thereon may then be assembled singly or in groups, by interfolding or otherwise into completed articles.

Other objects and characteristic features will appear from the following detailed description of one embodiment of the invention taken in connection with the accompanying drawing in which the same reference numerals are applied to' identical parts in the several figures and in which Fig. 1 is a diagrammatic view of a section of coil constructed in accordance with the invention and shown before folding;

Fig. 2 is a similar perspective view thereof partly folded;

Fig. 3 is a diagrammatic view in perspective of a finished coil;

' Fig. 4 is a view in section on the line 4-4 of Fig, 1 of the dielectric lamina before treatment;

Fig. 5 is a similar view showing the conductive ink in place;

Fig. 6 is a similar view after the electroplating operation; and

Fig. 7 is a view in perspective of an intercalary insulating lamina.

As herein disclosed a thin lamina or sheet it of cellophane or other dielectric material may be prepared for use as the base or carrier of a conductive trace I! by being precreased for sub-' sequent folding as at l3 and further by being provided, e. g. by punching, with perforations I4 which will subsequently be aligned to receive a core I! if desired. The lamina is herein shown geneous conductor.

as comprising five connected panels but may be of any continuous length as desired, and in prac tice will preferably have many more such panels in connected sequence. The perforation l4 may further be formed to have a notch l6 at one point 6 of one edge.

Upon the lamina thus prepared is then deposited a trace or outline ll of the desired conductor in a conducting medium. This may be most simply done by printing the trace with an 10 ink containing graphite or a metallic pigment in an adhesive medium, or the trace may be applied by stencilling, or by means of a transfer roller, or by decalcomania, or by any other satisfactory means. The trace is applied as indicated in the drawing to both sides of the lamina and on any one given panel will, in general, form two disconnected sections both ending at the same point of the perforation i 4 as indicated at l6. It will be understood that the dimensions of the lamina, 2o trace and conductor are strongly exaggerated transversely to the lamina in Figs. 4, 5 and 6 to clarify the structure. The trace upon each side of any given panel will, in general, be continuous with the trace upon the same side of one neighboring panel as indicated at IT, the trace passing without solution of continuity across the creases l3. Further to ensure against rupture of electrical continuity at the creases l3 when the lamina. is subsequently folded, it may in some cases be desirable to widen the trace across and in the immediate vicinity of the creases l3 as also indicated at IT. The trace may also be provided with enlarged portions as at i8 at its extremities to afford convenient contacts for ultimate attachment of leads l9 to the finished coil.

The lamina with the electrically conductive trace thereon is then immersed in an appropriate electroplating bath and the various sections of the trace are made simultaneous negative electrodes so that deposition of metal takes place simultaneously upon each pair of trace sections which terminate at any one common point l6 of the perimeter of a perforation M. It is found that deposition proceeds more rapidly at the very narrow neighboring edges 20 (Fig. 5) than for I example upon the broad faces 2| and 22 of the two sections of the trace. The principal result of this efiect is that the metallic deposit i2 grows acrossthe edge of the lamina at the point l6 as shown in Fig. 6 and thus unites the two sections of the metallic deposit on the two sides of the lamina into one continuous, jointless, homo.-

The lamina is removed from the electroplating apparatus when a sufllcient mass of conductor has been deposited thereon and is subjected to such washing and drying'processes as may be necessary or desirable.

The conductor bearing lamina thus prepared may then be assembled with a similar creased and perforated but otherwise untreated, i. e. conductor-less, lamina 23 applied to each face thereof and the three laminae folded together accordion fashion on the creases l3, thus intercalating a double insulating layer of conductorless dielectric between each two consecutive panels of the conductor bearing sheet. The whole may then be compressed, a core I! inserted and terminal leads ll attached to produce a finished coil as shown in Fig. 3. Or a single lamina 23 may be intercalated interfolding it with the lamina III with the folds of each lying atright angles to those of the other and embracing the upper and lower edges alternately of successive panels of the other, thus interposlng only one thickness of insulation between consecutive conductor bearing panels.

As herein disclosed the invention is shown embodied in a self-inductive coil. It is evident that the self inductiveness depends only upon the dis-, position or directions of turn of the conductor spiral sections upon consecutive panels and the coil could equally well be non-self inductive. So also the drawing shows conductor spirals of one turn only for simplicity and clearness, but selfevidently the spiral on each panel is limited as to number of turns only by the relative dimensions of its parts. Indeed it is not essential to the invention that the completed structure be a coil at .all. The invention applies to many possible arrangements in which a pair of electrically con- 5 ducting members are separated by. a dielectric member except for conductive connection across the dielectric at substantially small portions thereof. The embodiment herein disclosed is illustrative merely and maybe departed from and 10 modified in many ways without departing from the spirit and scope of the invention as pointed out in and limited only by the appended claim.

What is claimed is:

As a new article of manufacture, a lamina of i5 dielectric material comprising a hinged sequence of panels folded together, an insulating sheet disposed between two consecutive panels, a narrow band of conductive material disposed upon each face of each of the two consecutive panels so that each of the two bands upon one of the said panels extends to a common point on an edge of the panel and so that one band upon one of the two panels is continuous with one band upon the other panel on the same side thereof,- and a conductive coating uponthe four, bands and continuous on both sides andacross an edge-of the lamina at each of thetwo common point each suchband and coating being enlargedin width where they cross a hinge between consecutive panels.

ERWIN E. FRANZ. 

